The present invention relates to a method for producing a basic amino acid-modified organopolysiloxane, and more particularly to a method for the efficient production of a basic amino acid-modified organopolysiloxane having carboxy groups and amino groups derived from amino acids.
Examples of methods for producing amino acid-modified organopolysiloxanes include methods in which N-acylamino acids and organopolysiloxanes containing intramolecular alkyl halide groups are allowed to react in an aprotic polar solvent (see Japanese Patent Application Laying Open No. Sho 50-158700), methods in which amino acids and organopolysiloxanes whose hydroxyl groups are bonded to intramolecular carbon are allowed to react in the presence of an acid catalyst (see Japanese Patent Application Laying Open No. Sho 52-3023), and methods in which amino acids with protected carboxy groups and organopolysiloxanes containing intramolecular epoxy groups are allowed to react with each other (see Japanese Patent Application Laying Open No. Sho 52-114699).
The methods proposed in Japanese Patent Application Laying Open No. Sho 50-158700 and Japanese Patent Application Laying Open No. Sho 52-3023 are disadvantageous, however, in that because the carboxy groups of the amino acids are involved in the reaction, the carboxy groups derived from the amino acids are absent from the resulting amino acid-modified organopolysiloxanes, which thus lack the properties normally associated with amino acids. In addition, the methods proposed in Japanese Patent Application Laying Open No. Sho 52-114699 are disadvantageous in that the carboxy groups of the amino acids must be protected in the form of alkali metal salts, and the alkali metals must be removed from the resulting amino acid-modified organopolysiloxanes.
Specifically, an object of the present invention is to provide a method for the efficient production of a basic amino acid-modified organopolysiloxane having carboxy groups and amino groups derived from amino acids.
The present invention relates to a method for producing a basic amino acid-modified organopolysiloxane comprising reacting (A) a basic amino acid with (B) an organopolysiloxane having carboxylic anhydride groups bonded to silicon atoms.